1. Description of the Prior Art
In view of environmental problems arising from the widespread use of insecticides to control undesirable insects, attention has turned in recent years to other insect control techniques including the use of sex attractant pheromones for trapping insects or disrupting their reproductive cycle. Therefore, research has turned to the identification of the chemicals found in nature which are sex attractants for various insect species and to the commercial synthesis of such compounds and their mimics, i.e., compounds which imitate the sex attractant effect of the natural compounds although having a different chemical structure.
The Heliothis complex, such as, Heliothis zea (corn earworm), Heliothis virescens (tobacco budworm), and Heliothis armigera includes some of the pests most damaging to valuable agricultural in this country and other parts of the world.
Reserchers have determined that a combination of cis-9-tetradecenal and cis-11-hexadecenal is a sex attractant for males of the species Heliothis virescens and that a combination of cis-11-hexadecenal with several other components has similar attractant properties with respect to Heliothis zea. See U.S. Pat. No. 3,952,093, Roelofs et al, issued Apr. 20, 1976. See also Klem et al, Entomological Society of America presentation, Houston, Tex., Nov. 29, 1978. Other sex pheromones for other insect species bearing some chemical similarity to cis-9-tetradecenal and cis-11-hexadecenal are described in U.S. Pat. Nos. 3,866,349, Meijer et al, issued Feb. 18, 1975, 3,980,771, Meijer et al, issued Sept. 14, 1976, 4,042,681, Underhill, issued Aug. 16, 1977, and 4,059,689, Struble, issued Nov. 22, 1977.
The synthesis of the cis-9-tetradecenal and cis-11-hexadecenal sex attractants for Heliothis virescens and Heliothis zea as described in U.S. Pat. No. 3,952,093 is fairly complex and the chemicals are expensive. When released into the atmosphere of infested areas, these chemicals confuse males seeking females for mating thereby disrupting the mating of the insects.
2. Field of the Invention
Applicants have found surprisingly that an effective sex pheromone mimic for the Heliothis complex is provided by n-tetradecyl formate, CH.sub.3 (CH.sub.2).sub.13 OCHO, a relatively inexpensive chemical. Unlike the peromones of U.S. Pat. No. 3,952,093, n-tetradecyl formate has no double bonds at all in the carbon chain and would not be expected to behave as the sex pheromone mimic for the Heliothis species and to disrupt mating of the insects.
Accordingly the object of the present invention is to provide as an effective sex pheromone mimic for male moths of the Heliothis complex the compound n-tetradecyl formate and its compositions. A further object of the invention is to provide a method for controlling insects of the Heliothis complex by using n-tetradecyl formate and its formulations to disrupt the reproductive cycle of the species.